Inflation and sealing device for inflatable air cushions

ABSTRACT

The invention is directed to a device for inflating and sealing an inflatable structure, such as inflatable cushions. The device includes an assembly configured for inflating a cushion cavity disposed between first and second layers of a film, and a sealing mechanism that preferably includes a rotary sealing drum, which can include a heat source.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/858,550 filed Sep. 20, 2007, now U.S. Pat. No. 8,128,770, whichclaims the benefit of provisional application No. 60/846,188, filed onSep. 20, 2006, the contents of which are hereby incorporated herein byreference thereto.

FIELD OF THE INVENTION

The present invention relates to the manufacturing of packagingmaterials, and more particularly to a device for inflating and sealinginflatable air cushions that are used as packaging materials. Thisapplication claims the benefit of provisional application No.60/813,363, filed on Jun. 14, 2006, and is a continuation of theInternational PCT Application entitled Vehicle Propulsion SystemActivation Device, filed on Jun. 12, 2007, the contents of which arehereby incorporated herein by reference thereto.

BACKGROUND OF THE PRESENT INVENTION

Devices are known for inflating flexible structures, such as inflatableair cushions or pillows (hereinafter referred to as “cushions”) that areused to provide added protection to an object during packaging andtransportation of fragile articles. It is desirable that devices formanufacturing such inflatable cushions be compact, reliable, and easy tooperate. Additionally, it is desirable that the inflatable cushionsthemselves be quickly manufactured and adequately inflated and sealed toreduce the likelihood of leaking, and thus loss of their protectiveproperties.

One example of a such a device is disclosed in U.S. Pat. No. 6,209,286to Perkins et al. The device is a continuous motion device that usesdrive rollers to advance preformed sheet material through the device.The device includes a pair of idler rollers that are crowned in thecenter for keeping the central section of the sheet material laterallytaut to prevent bunching up of the material at the drive rollers. Thedevice seals the sheet material after inflation by moving the materialpast a seal forming apparatus where heat and light pressure are linearlyapplied to contact the upper surface of the sheet material and form aseal therein.

Thus, there is a need for a device for adequately inflating and sealinginflatable, flexible structures, such as air-filled cushions, withincreased speed and reliability.

SUMMARY OF THE INVENTION

The present invention is directed to a device for inflating and sealingan inflatable, flexible structure. In the preferred embodiment, theinflatable-cushion inflation and sealing device includes an inflationassembly configured for inflating with a fluid a cushion cavity disposedbetween first and second layers of a film, and a sealing mechanism thatincludes a rotary sealing drum, which includes a heat source and has aperiphery. The sealing mechanism is configured for receiving overlappingedge portions of the first and second film layers adjacent the inflatedcushion cavity, and directing the edge portions about the sealing drumto hold the edge portions against each other sufficiently tightly tokeep the fluid from escaping from between the edge portions. The sealingmechanism is also configured to seal the edge portions to each otherusing the heat source over a heating portion of the sealing drumperiphery that is at least about 40% of the periphery to form alongitudinal seal configured to seal the fluid in the cushion cavity.

Preferably, the heat source is configured to provide heat sufficient toseal the edge portions along the entire heating portion. The sealingmechanism preferably includes at least one belt in tension around thesealing drum to press the edge portions against the sealing drum andeach other for longitudinally sealing the edge portions. The sealingmechanism is also preferably configured for sealing the film at a rateof at least 70 ft/min. Also, the rotary sealing drum preferably includesa circumferential outer surface that is substantially smooth.

In one embodiment, the film has a major surface extending longitudinallyand transversely to an inflation path, the edge portions are joinedtogether, the inflation assembly comprises a fluid conduit configuredfor reception longitudinally between the joined edge portions, and thedevice further comprises a cutter configured and oriented to cut theedge portions apart from each other at a location about the fluidconduit disposed at less than about 90° from a direction orthogonal tothe major surface of the film. Preferably, the cutter includes a blade.The film is preferably pulled in a direction that is away from the majorsurface of the film after cutting so that the film is pulled against thecutter during cutting.

In another embodiment, the device further includes first and secondtension rollers disposed on a transversely opposite side of the filmfrom the edge portions and configured for gripping an opposite edge ofthe film. The tension rollers are oriented at an angle to a directiontransverse to the inflation path to bias said opposite edge away fromthe edge portions to improve airflow into the cushion cavity.

In another preferred embodiment, the sealing drum is also configured toseal the edge portions to each other using the heat source to form alongitudinal seal configured to seal the fluid in the cushion cavity,wherein the heat source is configured to provide substantiallycontinuous heat sufficient to seal the edge portions.

In yet another preferred embodiment, the sealing mechanism includesfirst and second belts configured and disposed for nipping there betweenoverlapping edge portions of the first and second film layers adjacentthe inflated cushion cavity the edge portions to keep the fluid fromescaping from between the edge portions. The belts are also configuredfor directing the edge portions about a curved path, and a heatingelement is disposed along a curved portion of the curved path and isoperable to heat the edge portions sufficiently to seal the edgeportions for sealing the fluid in the cushion cavity.

The sealing drum of the device can include the heating element, and thefirst and second belts are configured for directing the edge portionsabout the sealing drum to hold the edge portions against each othersufficiently tightly to keep the fluid from escaping from between theedge portions, and for sealing the edge portions to each other. In analternative embodiment, a heating element, such as a heating block witha concave surface, can hold the belts against the drum to provide theheat. Preferably, the sealing drum has a belt supporting portion andsealing portion that is configured for longitudinally heat sealing theedge portions together. The first belt is preferably disposed betweenthe second belt and the belt supporting portion, and has a first widthtransverse to the path, and the second belt has a second widthtransverse to the path and wider than the first width. The second beltis preferably disposed to pinch a pinched part of the edge portionagainst the first belt and to pinch a sealed part of the edge portionagainst the sealing portion of the sealing drum. Preferably, the pinchedpart of the edge portion is disposed transversely between thelongitudinally sealed part of the edge portion and the cushion cavity.

The sealing mechanism can also include a plurality of rollers configuredfor maintaining the first and second belts in tension sufficient to holdthe edge portions against each other to keep the fluid from escapingfrom therebetween. The rollers also direct the belts about the sealingdrum. In another embodiment, the first and second belts are configuredsuch that the path includes a sealing segment and a cooling segment. Inthe sealing segment, the belts preferably hold the edge portions againstthe sealing drum to seal the edge portions, and in the cooling segment,located downstream of the sealing segment, the belts direct the sealededge portions away from the sealing drum to allow the edge portions tocool. The belts preferably pinch the edge portions together to keep thefluid from escaping from the cushion cavity in each of the sealing andcooling segments. More preferably, the belts are configured such thatthe path includes an intake segment upstream from the sealing segment,in which the belts pinch the edge portions in an unsealed state to keepthe fluid from escaping from the cushion cavity. Preferably, the path iscurved along each of the intake, sealing, and cooling segments.

In another embodiment, the belts are configured such that the pathincludes an intake segment, in which the belts pinch the edge portionsin an unsealed state to keep the fluid from escaping from the cushioncavity, and a sealing segment, located downstream of the intake segment,in which the belts hold the edge portions against the sealing drum toseal the edge portions. Preferably, the belts pinch the edge portionstogether to keep the fluid from escaping from the cushion cavity in eachof the intake and sealing segments, and the device further includes acutter configured and disposed for cutting the edge portions from eachother in the intake segment after the first and second belts nip theedge portions therebetween.

In yet another preferred embodiment, the device includes an inflationassembly configured for inflating with a fluid a cushion cavity that isdisposed between first and second layers of a film, a sealing mechanismconfigured for nipping overlapping edge portions of the first and secondfilm layers adjacent the inflated cushion cavity and forming alongitudinal seal between the film layers, and a cutter disposedupstream of the sealing mechanism and configured for cutting the edgeportions from each other after nipping, but prior to sealing.Preferably, the sealing mechanism is configured for moving the edgeportions along a sealing path that includes an intake segment and asealing segment. The sealing mechanism is also configured for holdingthe edge portions against each other in an unsealed state in the intakesegment to keep the fluid therebetween prior to the sealing thereof,wherein the sealing mechanism is configured for sealing the edgeportions together in the sealing segment, which is downstream from theintake segment; and the cutter is disposed along the intake segment.

In yet another preferred embodiment, the inflation and sealing deviceincludes an inflation assembly configured for inflating with a fluid acushion cavity disposed between first and second layers of a film, asealing mechanism configured for sealing overlapping edge portions ofthe first and second film layers adjacent the inflated cushion cavity;and a tension member disposed on a transversely opposite side of thefilm from the edge portions and configured for gripping an opposite edgeof the film to bias said opposite edge away from the edge portions toimprove airflow into the cushion cavity. Preferably, the tension memberincludes first and second tension rollers oriented at an angle to adirection transverse to the inflation path to bias said opposite edgeaway from the edge portions.

The present invention is also directed to a method of inflating andsealing an inflatable cushion, a preferred embodiment includinginflating a cushion cavity with a fluid, the cavity being disposedbetween first and second layers of a film. The method also includesdirecting overlapping edge portions of the first and second film layersadjacent the inflated cushion cavity about a rotary sealing drum to holdthe edge portions against each other sufficiently tightly to keep thefluid from escaping from between the edge portions, and using a heatsource over a heating portion of a sealing drum periphery that is atleast about 40% of the periphery to form a longitudinal seal configuredto seal the fluid in the cushion cavity.

The present invention thus provides a device for inflating and sealingcushions at relatively high speed and with increased reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of another preferred embodiment of a filmof uninflated cushions that can be inflated and sealed by a deviceconstructed according to the present invention;

FIG. 2 is a perspective view of a preferred embodiment of a film ofcushions after inflation and sealing by a device of the presentinvention;

FIG. 3 is a schematic, side view of a preferred embodiment of aninflation and sealing device of the present invention;

FIG. 4 is a schematic, top view thereof;

FIG. 5 is a perspective, left-rear view of a preferred embodiment of aninflation assembly of the present invention;

FIG. 6 is a bottom view thereof, showing the inflation pipe assemblyassociated with the inflation channel of the film of FIG. 1;

FIG. 7 is a rear view thereof;

FIG. 8 is a schematic, rear view of a preferred embodiment of a sealingmechanism, showing the sealing mechanism associated with anotherembodiment of a film of cushions; and

FIG. 9 is another schematic, rear view thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a device for inflating and sealinginflatable, flexible structures. A variety of suitable inflatablestructures or cushions are well known and used for protective packagingapplications. Several preferred film structures are disclosed in U.S.application Ser. No. 11/123,090, which form inflatable cushions withlongitudinal axes that can be, for instance, oriented longitudinally,transversely, or in any other pattern with respect to the longitudinalaxis of the film.

A preferred embodiment of a film for inflatable cushions that issuitable for use with the device of the present invention is shown inFIG. 1. Film 10 of uninflated material has a series oftransversely-oriented cushions attached at perforated edges, as shown inFIG. 2. The film 10 may be made of a variety of different materials,including materials such as polyethylenic resins such as low densitypolyethylene (LDPE), linear low density polyethylene (LLDPE), and highdensity polyethylene (HDPE); metallocenes; and ethylene vinyl acetates(EVA); and blends thereof.

The film 10 has a first longitudinal edge 12 and a second longitudinaledge 14, both of which are preferably closed or joined. The film 10 hasa lead end 6, and also includes generally transverse seals 16 andperforations 18. The transverse seals 16 join a first film layer 20,such as a top layer, of the film 10 to a second film layer 22, such as abottom layer, of the film 10 along the seals, and together with theclosed, second longitudinal edge 14, define an inflation cavity of eachcushion 28. The first and second film layers 20,22 define a majorsurface or plane of the film 10. The transverse perforations 18perforate the film 10 through the first and second film layers 20,22 tofacilitate later separation of each cushion 28 from each other.

In the embodiment shown in FIG. 1, the transverse seals 16 begin at thesecond longitudinal edge 14 of the film 10, and extend transversely to adistance 9 from the first longitudinal edge 12. The distance 9 ispreferably at least about 0.25 inches and at most 1.0 inches, and morepreferably at least about 0.30 inches and at most about 0.70 inches,though greater or smaller distances can be used in differentembodiments. In the preferred embodiment, the distance 9 is from about0.50 to about 0.60 inches.

Because the transverse seals 16 do not extend all the way to the firstlongitudinal edge 12 of the film 10, an opening 24 is defined betweeneach end of a transverse seal 16 and the first longitudinal edge 12 ofthe film 10. The area of the film 10 between the openings 24, andbetween overlapping film layers adjacent the first longitudinal edge 12,defines a continuous, longitudinal inflation channel 23 having a widthdefined by distance 9. The lead opening 24 is generally used, to feedthe inflation channel 23 of the film 10 over an inflation nozzle of aninflation device when loading the film to the device. The width of theinflation channel 23 is preferably configured to produce a tight, or insome embodiments a friction-fitting association, over the inflationnozzle to prevent or substantially reduce air leakage during inflation.Advantageously, this reduces the amount of compressed air required forinflation, and minimizes the size of the compressor and power utilityrequirements of the inflation device.

In FIG. 2, each inflated cushion 28 is separated from a neighboringinflated cushion by a transverse perforation 18. As a remnant of themanufacturing process explained below, small cutaway flaps 27 are lefton the inflated film 10 adjacent to the first longitudinal edge 12. Themanufacturing process also forms a longitudinal seal 29 along a sealingor edge portion 8 of the inflated film 10 (defined by the overlappingedge portions of each film layer 20,22), so that each inflated cushion28 is sealed closed, trapping the inflation fluid, which is preferably agas and more preferably air, within the cushions. The longitudinal seal29 is preferably substantially straight, but in other embodiments, theseal can have a curved, zig-zag, or other orientation.

The film 10 also has a width 15, and a perforation-to-perforation length17, which may be altered depending on the particular type of cushionbeing manufactured. Preferably, the width 15 of the film 10 is at leastabout 6 inches and at most about 36 inches, more preferably is at leastabout 12 inches and at most about 24 inches, and in the preferredembodiment, the width 15 is about 18 inches, although other widths canbe used. The perforation-to-perforation length 17 is preferably at leastabout 4 inches and at most about 24 inches, and is more preferably atleast about 8 inches and at most about 12 inches, although other widthscan be used.

In one embodiment, the first and second film layers 20,22 are attachedto each other along the second longitudinal edge 14, but are unattachedto each other along the first longitudinal edge 12, prior to inflation.Such a configuration can be formed from a single layer of film material,a flattened tube of film material with one edge slit open, or twoseparate layers of film material. For example, the first and second filmlayers 20,22 can include a single sheet of film material that is foldedover itself to define the attached second longitudinal edge 14 (i.e.,“c-fold film”).

Referring to a preferred embodiment shown in FIGS. 3 and 4, the device30 includes a device housing 32, a film staging mechanism 40, afeed-assisting mechanism 50, an inflation assembly 70, and a sealingmechanism 90. Although the device 30 can be used to inflate a variety offilm structures having different configurations, the remaining sectionsof the application will describe the device with respect to inflation ofthe preferred film embodiment shown in FIG. 1.

The staging mechanism 40 is preferably configured for loading a bulksupply of film of uninflated cushions. As shown in FIG. 3, theuninflated film 10 is provided as a roll 11. Preferably, the stagingmechanism 40 can accommodate rolls of film 11 that are at least about 9inches in diameter, are more preferably at least about 12 inches indiameter, and are even more preferably at least about 18 inches indiameter. In the preferred embodiment shown in FIG. 3, the roll 11 has adiameter of 9 inches. In other embodiments, the staging mechanism canaccommodate a roll of film with other dimensions, or a supply of filmthat is provided in other bulk forms, for example as a continuous stackof film material.

The staging mechanism 40 preferably includes a cradle that is formed bya pair of staging rollers 42,44 extending transversely from the housing32 and spaced apart from each other, as shown in FIGS. 3 and 4. In thisconfiguration, the staging rollers 42,44 can support the roll of film 11therebetween. The spacing 43 between the staging rollers 42,44 can beadjustable or selected depending on the diameter of the roll 11 that isto be supported therebetween. Preferably, the spacing 43 is greater thanthe core diameter 13 of the roll 11. The staging mechanism 40 alsopreferably includes a tray 46 disposed between the staging rollers42,44, and preferably also extending from the housing 32. The tray 46preferably has a concave, bent, or v-shaped configuration, and isconfigured to catch or receive the core of the roll 11 once the film isremoved or depleted therefrom. In other embodiments, the stagingmechanism 40 can include a fixed roll axle or pin member configured forreceiving and supporting the core of the roll thereon.

The staging mechanism 40 can also include other rollers, preferably alsoextending from the housing 32 and positioned between the staging rollers42,44 and the feed-assisting mechanism 50, that are configured fordirecting the film from the staging mechanism 40 to the feed-assistingmechanism 50. The film 10 is generally pulled from the roll 11 anddirected through the device 30 by a drive mechanism in the downstreamdirection or path A, as shown in FIGS. 3 and 4, and the major surface ofthe film 10 preferably extends substantially longitudinally andtransversely to the direction A.

In the preferred embodiment, the staging mechanism 40 includes a fixedroller 47, which is preferably positioned below the staging rollers42,44, and guide roller 48, which is preferably positioned at level withthe feed-assisting mechanism 50. The fixed roller 47 and guide roller 48are positioned and configured to preferably guide the film 10 away fromthe supply roll 11 and steadily toward the feed-assisting mechanism 50,all the while keeping the film in constant tension. The guide roller 48is also preferably positioned upstream relative to the feed-assistingmechanism 50 and inflation assembly 70 such that the guide roller 48blocks any air expelled from the inflation assembly 70 from reaching thesupply roll 11.

The feed-assisting mechanism 50 is preferably configured to direct andmanipulate the film 10 within the device 30 just prior to and duringinflation. The feed-assisting mechanism 50 is preferably configured forgripping the film 10, preferably at or adjacent to the secondlongitudinal edge 14 to bias the edge away from the first longitudinaledge 12 during inflation to improve airflow into the cushion cavities.Preferably, the feed-assisting mechanism 50 includes a tension member,such as a pair of tension rollers 52,54, positioned in the device 30transversely opposite of the inflation assembly 70, and extending fromthe housing 32. The tension rollers 52,54 are preferably positionedsubstantially on top of each other such that the second longitudinaledge 14 of the film 10 can pass and be rolled therebetween as the film10 is directed in the downstream direction A. In the preferredembodiment, the rollers 52,54 are preferably free-spinning, but in otherembodiments, the two rollers can be associated with a drive mechanism toaid in driving the film downstream from the roll and through theinflation device.

The tension rollers 52,54 preferably extend from the housing 32 suchthat the rotational axis 55 of the rollers 52,54 is at an angle 56 fromthe orthogonal to the downstream direction A of the film 10 through thedevice 30. The angle 56 is preferably at least about 2° and at mostabout 20° from orthogonal, and as shown in FIG. 4, the angle 56 is fromabout 5° to about 10° from orthogonal. In this angled configuration, therollers 52,54 pull the second longitudinal edge 14 of the film 10 awayfrom the inflation assembly 70 as the film 10 passes and is rolledbetween the rollers 52,54 in the downstream direction A. By pulling thesecond longitudinal edge 14, and with the inflation channel 23 over theinflation nozzle of the inflation assembly, the first and second layers20,22 of the film are substantially flat and taught during inflation.This unsticks the layers 20,22 from each other, which stickage canprevent or substantially impede the flow of air into the cushioncavities. The rollers 52,54 are especially useful in unsticking the filmlayers when the axes of the cushions are longitudinally orientedparallel to the longitudinal axis of the film, or when the film hasother complex cushion patterns or orientations, Regardless of theorientation of the cushions, the unsticking of the film layers by thefeed-assisting mechanism advantageously also allows inflation of thefilms at higher speeds, and inflation of films having thinner first andsecond film layers, which tend to be more sticky, while minimizing thenecessary inflation pressure. The tension rollers 52,54 have been foundto be particularly advantageous when used with narrow and deep inflationcavities, such as with inflation cavities that have a depth (in thelateral direction) of more than twice the width (in the longitudinaldirection), or at least three or four times the width. In otherembodiments, the tension rollers can be used with a different type ofsealing mechanism, such as a linear sealing mechanism.

The inflation assembly 70 is preferably mounted to the housing 32 andpositioned on a transversely opposite side from the feed-assistingmechanism 50. Additionally, the inflation assembly 70 is positionedwithin the device 30 such that it is generally aligned with firstlongitudinal edge 12 and the inflation channel 23 as the film 10 isdirected through the device 30. The inflation assembly 70 is configuredand oriented for inflating each cushion cavity 28 of the film 10 with afluid, which is preferably a gas, and more preferably is air.

As shown in FIGS. 5-7, the inflation assembly 70 preferably includes afluid conduit or nozzle 72, which is preferably tubular and extends in alongitudinal direction that is generally parallel to the downstreamdirection A of the moving film 10. As shown in FIG. 7, the nozzle 72 isheld within a gap 71 of the nozzle housing 74, and is secured therein,such as by fastener 75. The nozzle housing 74 is preferably secured tothe device housing 32, and as shown in FIG. 7, the nozzle housing 74 issecured via a pair of openings 77 that are configured to receivefasteners. The device housing 32 preferably contains an air compressor33 or other similar compressed fluid, gas, or air source, which isconnected to the nozzle 72 for delivering inflation air therethrough.Other embodiments can secure the compressed air source in differentconfigurations, which can include an external compressed air source.

The nozzle 72 is preferably aligned with the inflation channel 23 of thefilm 10. Preferably, the nozzle 72 has an outer diameter 69 that isconfigured for a tight, and more preferably friction-fitting, receiptwithin the inflation channel 23. More preferably, the outer diameter 69is at least about 0.15 inches and at most about 0.75 inches, and is evenmore preferably at least about 0.25 inches and at most about 0.5 inches.In the preferred embodiment, the outer diameter 69 is about 0.30 inches.In other embodiments, however, the nozzle can be removed from the nozzlehousing and replaced with a nozzle of a different outer diameter,depending on the configuration of the cushion and inflation channel ofthe film to be inflated. The nozzle 72 can also have a taperedconfiguration. The upstream nozzle tip 67 is preferably rounded,although in other embodiments, the nozzle tip can have otherconfigurations, and the tip 67 is preferably positioned just downstreamof the feed-assisting mechanism 50, on the opposite side thereof.

The nozzle 72 includes an outlet from which air is expelled to inflatethe cushion cavities of the film 10. Preferably, the outlet is inflationslot 73 that runs along a portion of the longitudinal length of thenozzle 72, and is positioned to direct air substantially transverselyinto the cushion cavities. More preferably, the inflation slot 73 has alength 68 that is longer than the perforation-to-perforation length 18of the film 10 to maximize the inflation efficiency of the air expelledfrom the inflation slot 73 and into the cushion cavities. Preferably,the cushions 28 are filled with air at an inflation pressure of at leastabout 3 psi, and more preferably at an inflation pressure of at leastabout 5 psi. In the preferred embodiment, the inflation pressure of thecushions 28 is between about 5 psi and about 8 psi, but otherembodiments can inflate the cushions at even greater inflationpressures.

The inflation assembly 70 also includes a cutting element, which ispreferably a blade 76. As shown in FIGS. 3-7, the blade 76 is preferablydisposed and secured within a blade slot 79 that is defined in thetubular wall of the nozzle 72. The nozzle preferably has a tubular wallthickness that is at least about 0.01 inches and at most about 0.07inches, and is more preferably is about 0.03 inches. Blade slot 79 ismachined within the tubular walls preferably without creating or byminimizing leaks from the nozzle 72. The blade 76 is positioned alongthe nozzle 72 downstream from both the inflation slot 73 and first andsecond insertion idler rollers 92,94 of the sealing mechanism 90.Preferably, the blade 76 is positioned immediately downstream from theaxis 93 of the insertion idler roller 92, is more preferably less thanabout ¼ inch downstream, and in the preferred embodiment. is about ⅛inch downstream of the axis 93. In this configuration, the film 10 isfirmly held by the sealing mechanism 90 prior to cutting the film 10 andreleasing it from association with the inflation assembly 70. The blade76 is also preferably positioned upstream from the sealing mechanism 90.

Additionally, the blade 76 is preferably disposed about the nozzle 72 onthe opposite side from the inflation slot 73. Preferably, the blade 76is substantially vertical or parallel with the vertical plane V (inembodiments in which the lateral width of the film is generallyhorizontal) that is orthogonal to the major surface of the film 10. Theblade 76 can also be at an angle 80 from the vertical plane V, as bestshown in FIG. 7. Preferably, the angle 80 is less than about 90° fromthe vertical plane V, and in the preferred embodiment, the angle 80 isfrom about 60° to about 70° from the vertical plane V. Put another way,the blade 76 is preferably disposed about the nozzle 72 from betweenabout 12 o'clock and about 6 o'clock, and more preferably from betweenabout 1 o'clock and about 2 o'clock when looking downstream. In thisconfiguration, the blade 76 cuts the film 10 after inflation of thecushions 28 and nipping between the first and second insertion idlerrollers 92,94. More preferably, the blade 76 cuts a portion of the firstor second film layers 20,22 near or adjacent to the first longitudinaledge 12 of the film 10 (i.e. at or adjacent to the sealing or edgeportion 8), as the film 10 is directed in the downstream direction A. Bycutting a portion of the film 10, the inflation assembly 70 is releasedfrom association with the inflation channel 23 of the inflated film 10(i.e. between the film layers 20,22), and can proceed through the rotaryscheme of the sealing mechanism 90.

Optionally, the inflation mechanism can also include a film drag tensionmechanism positioned immediately upstream of the insertion idler rollersof the sealing mechanism. For example, the film drag tension mechanismcan be adjustable and include a felt material, preferably havingdimensions of 1 inch×1 inch, that is configured to engage and flattenthe film prior to engagement with the sealing mechanism. This preventsor substantially reduces the formation of any wrinkles in the film foreasier subsequent sealing, and can improve the sealing of air about thenozzle.

The sealing mechanism 90 is positioned within the device 30 downstreamof the inflation slot 73 of the inflation assembly 70 so that thecushions 28 of the film 10 are sealed after being inflated. Preferably,the sealing mechanism 90 includes an arrangement of rollers, belts, anddrums that is configured to nip and hold the film 10 at a feeding zone96, and to direct the film 10 in the direction or path A that isgenerally curved. The curved path is preferably defined by differentsegments or areas, including an intake segment, a sealing segment, and acooling segment. The film 10 is directed through and around the intake,heating, and cooling segments before finally being released as a sealedfilm 10 at an exit zone 98 of the sealing mechanism 90. Preferably, thesealing mechanism 90 is substantially aligned with the inflationassembly 70 such that the film 10 is nipped and securely held alongsealing or edge portion 8, which includes or is adjacent to theinflation channel 23 and first longitudinal edge 12. Preferably, thesealing mechanism 90 is configured for forming a substantiallylongitudinal seal 29 in the film 10, however, in other embodiments, thesealing mechanism can be configured for forming a seal that has acurved, zig-zag, or other orientation.

The sealing mechanism 90 preferably includes a feeding zone 96 where thesealing portion 8 is placed between first and second drive belts100,102. Referring to FIG. 3, the first drive belt 100 is preferablydriven in the belt direction B, and the second drive belt 102 ispreferably driven in the belt direction C, such that the film isgenerally directed in the downstream direction A through the sealingmechanism 90 after being inserted and nipped at the feeding zone 96. Thefirst and second drive belts 100,102 are preferably driven by respectivefirst and second nip rollers 104,106, which are associated with drivemechanisms that preferably include a gear and motor system housed in thedevice housing 32 for each nip roller. Alternatively, both first andsecond nip rollers 104,106 can be driven by a single drive mechanism. Inone embodiment, only one of the first and second nip rollers 104,106 isdirectly driven by a gear and motor system, while power is transferredto the other nip roller by another gear system. As shown in FIG. 10,each of the first and second nip rollers 104,106 preferably includeraised edges 132 that define a belt groove therebetween. The raisededges 132 advantageously help maintain the first and second belts100,102 in the belt groove and in association with the nip rollers, evenwhen the nip rollers are driven at high rotational speeds.

The first drive belt 100 preferably has a narrower transverse width thanthe second drive belt 102. This difference in transverse width allows aseal part 7 of the sealing portion 8 of the film 10 to be exposed anddirectly contacted by the heating element 116 of the sealing drum 110during sealing, while the portion of the second drive belt 102 thatextends past the first drive belt 100 pinches or presses the seal part 7of the sealing portion 8 against the heating element 116 to form theseal. The portion of the second belt 102 that overlaps the first drivebelt 100 preferably pinches a pinched part 6 of the sealing portion 8,which is preferably disposed transversely between the seal part 7 andthe cushion cavities 28 as shown for example in FIG. 8, against thefirst drive belt 100 and sealing drum 110 sufficiently tightly to keepthe fluid from escaping from the cushion cavities while the sealingportion 8 is directed to and around the sealing drum 110. The film 10shown in FIG. 8 is exemplary of another embodiment of a film of cushionsthat can be used with device 30, the film 10 having cushions 28 withlongitudinal axes that are parallel to the longitudinal axis of the film10.

In the preferred embodiment, the width of the first drive belt 100 is atleast about ¼ inch and at most about 1.0 inch, and more preferably is atleast about ½ inch and at most about ¾ inch. In the preferredembodiment, the first drive belt 100 is about ⅝ inch wide. The seconddrive belt 102 preferably has a width that is similar to the width ofthe sealing portion 8 of the film 10. Preferably, the width is at leastabout ½ inch and at most about 1 and ½ inch, and more preferably is atleast about 1.0 inch and at most about 1 and ¼ inch. In the preferredembodiment, the second drive belt 102 is about 1 and ⅛ inch wide. Otherembodiments can use first and second drive belts having differenttransverse widths.

The first and second drive belts 100,102 preferably have a similar beltthickness of at least about 0.02 inches, and more preferably at leastabout 0.05 inches. In a preferred embodiment, the belts have a thicknessof about 0.07 inches. Such belt thicknesses provide several advantages,including maintaining a sufficient stiffness of the belts 100,102 toensure hold back and containment of the air within the inflated cushioncavities. The belt thickness also allows the belts 100,102 to properlytrack on the crowned rollers of the sealing mechanism 90, and minimizesthe effect of the belts 100,102 on the drive pitch diameter.

The first and second drive belts 100,102 are preferably made of arelatively non-wearable material to promote extended life of the belts,preferably greater than 100 hours, before replacement. For example, thedrive belts 100,102 can be made of TEFLON® or a silicon composite, oralternatively have a TEFLON® or silicon-laminated surface. Morepreferably, the second drive belt 102 has a SILAM K® silicone surface,for example as sold by Ammeraal Beltech, Inc., or similar surface thatis able to withstand continuous 390° F. operating temperatures due toits proximity to the heating element of the sealing drum.Advantageously, this extends the life of the belt despite the increasedtemperatures applied to the belt to conduct heat to the film material,and/or the heat friction that results due to contact with the filmmaterial. Additionally, it was found that the surface of the first drivebelt 100 works best if it has a smaller frictional coefficient or isrelatively more slippery compared to the second drive belt 102 and thefilm 10 to allow the first drive belt to slip slightly as needed, suchas when there are differences in the pitch diameter at the variousrollers due to wrapping of the two drive belts 100,102 around a commonroller.

The feeding zone 96 is located between the first and second insertionidler roller 92,94, which respectively guide the first and second drivebelts 100,102 in their respective directions, and keep the belts intension, around the sealing drum 110. Preferably, the first and secondinsertion idler rollers 92,94 are positioned substantially on top ofeach other, and more preferably, the rollers 92,94 are slightly offsetfrom each other, with roller 92 positioned slightly upstream of roller94 to provide a small amount of give between the drive belts 100,102 toreceive the film 10 therebetween. Additionally, the insertion idlerrollers 92,94 are preferably positioned downstream of the feed-assistingmechanism 50 such that the angle 95 is defined between the axis ofrotation 93 of the roller 92 and the axis 97 (defined between the axis93 at the end of the roller 92 and the axis of rotation 55 at the end ofroller 52), as shown in FIG. 4, is at least about 30°, and is morepreferably at least about 45°.

Due to the position of the first and second insertion idler rollers92,94 at the feeding zone 96, the first and second drive belts 100,102preferably come together to nip and receive the film 10, and pinch thefirst film layer 20 and the second film layer 22 against each otheralong the sealing portion 8 as the film 10 is directed in the downstreamdirection A. Pinching of the film layers 20,22 sufficiently tightlyprevents air within the inflated cushion cavities from leaking duringthe rest of the sealing process. To provide a maximum pinching pressurebetween the belts 100,102 and the film layers 20,22, the spacing betweenthe insertion idler rollers 92,94 is preferably minimized to at mostabout 0.40 inches, more preferably to at most about 0.30 inches, and inthe preferred embodiment to about 0.25 inches.

After being nipped and pinched between the first and second drive belts100,102 at the feeding zone 96, the film 10 is directed along the intakesegment 117 of the path A, which is preferably curved, and morepreferably curved in a direction away from a plane that extendslongitudinally and transversely away from the nozzle 72. The intakesegment is preferably defined as the length of the path A downstream ofthe feeding zone 96 and upstream of the beginning of the sealing segment115. Preferably, the length of intake segment 117 is at least greaterthan a quarter of the surface circumference, is more preferably at leastgreater than half of the surface circumference, and is even morepreferably at least greater than double the surface circumference of theinsertion idler roller 94. Preferably, the blade 76 is located at oradjacent to the intake segment 117 so that the sealing portion 8 is cutsubstantially immediately after being nipped and pinched at the feedingzone 96.

After being cut, the film 10 is directed to the sealing segment 115 ofthe sealing mechanism 90, which includes a rotary sealing drum 110. Thesealing drum 110 is positioned downstream and preferably generally belowthe first and second insertion idler rollers 92,94 within the device 30.As is shown more clearly in the embodiments of FIGS. 8 and 9, thesealing drum 110 is preferably substantially cylindrical in shape, andincludes a circumferential outer surface 111 that is substantiallysmooth. The sealing drum 110 has a transverse width 109 that isapproximately the same as both the width of the second drive belt 102and the sealing portion 8 of the film 10.

The sealing drum 110 is in association with a rotary axle 112 that isconfigured for rotating the sealing drum 110 about axis 113. The rotaryaxle 112 is preferably associated with a drive mechanism 114 that isconfigured to rotate the axle 112, the drive mechanism including a gearand motor system that is preferably contained in the device housing 32.In other embodiments, the device does not include a drive mechanismconfigured to rotate the sealing drum, and the drum is instead dependenton the association with the drive belts for rotation.

The sealing drum 10 includes a sealing portion, which is preferablyheating source or element 116 that is disposed adjacent a beltsupporting portion 121 of the outer surface 111, and is longitudinallyaligned with the sealing portion 8 of the film. More preferably, theheating element 116 is mounted to or adjacent the outer surface 111 of aheating element supporting portion 131. The transverse width of the beltsupporting portion 121 is preferably greater than the width of theheating element support portion 131, but in other embodiments, thewidths can be of varying proportion. Preferably, the heating element 116can heat up to, or cool down from, the desired sealing temperature inless than about 8 seconds, more preferably in less than about 5 seconds,and in the preferred embodiment, in less about 2-3 seconds. This allowsthe device 30 to be started and stopped without an unnecessarily longstart/stop sequence. The heating element 116 also preferablycontinuously powered or heated to maintain a sealing temperaturethroughout the sealing process. Preferably, the sealing temperature ofthe heating element is at least about 300° C. and at most about 500° C.,is more preferably at least about 350° C. and at most about 425° C., andin the preferred embodiment is about 390° C. The heating element 116 isconfigured for associating with, and preferably positioned so that itdirectly contacts, the seal part 7 of the sealing portion 8 that is tobe sealed, and then transferring heat to the sealing portion 8 to meltor otherwise close and seal the film 10. The surface of the heatingelement 116 is preferably substantially smooth and continuous such thatit produces a seal with no gaps or pockets that would allow air toescape from the cushion cavities. The heating element 116 preferably hasa width 118 that is at least about 1/10 inch and at most about 1.0 inch,is more, preferably at least about ¼ inch and at most about ¾ inch, andin the preferred embodiment is about ½ inch.

The heating element 116 can include resistance sealing wires that areintegrated in the sealing drum to achieve its heating properties. In oneembodiment, each wire has a diameter of about 0.015 inches, and is madeof an alloy that is about 80% nickel and about 20% chromium. A series ofholes, preferably each about 0.06 inches in diameter, is drilled andspaced apart, preferably about 1.0 inch, around the sealing drum. Theresistance wires are bent down into each hole at a depth of about 0.12inches, and the remainder length of the wires lay across the surface ofthe sealing drum between the holes, which creates a stitched sealpattern. The resistance wires are preferably bonded into the holes tokeep the wires in place. This allows the wires to expand and retract astheir temperatures change. The series of wires can be spaced parallelfrom each other across the surface of the sealing drum, and the holes ofone wire can be drilled out of phase with those of an adjacent wire. Inother embodiments, the heating element can include a thermocouplefeedback or non-contact infrared temperature sensor to provide feedbackto a programmable logic controller to monitor the real-time temperatureof the heating element.

In another embodiment, the heating element 116 can be a custom “thinfilm” heater, such as one produced by Minco Corp. Such a heater usesthin, resistance alloy etching that is bonded to KAPTON®, for example assold by Dupont, and attached to aluminum foil. This technology alsoallows an integrated thermocouple to provide temperature feedback to aprogrammable logic controller.

In yet another embodiment, the heating element 116 can includetraditional resistance heaters, such as FIREROD® cartridge heaters, forexample as sold by Watlow Electric Manufacturing Co.; flexible, siliconrubber-based heaters; or the like. Such heaters, however, are not asdesirable due to their relatively slow heating properties.

The sealing drum 110 is configured for association with both the firstdrive belt 100 and the second drive belt 102, which is wider than thefirst drive belt 100, about its outer surface 111. As shown in FIGS. 8and 9, the first drive belt 100 preferably directly contacts the surface111 of the belt support portion 121 of the sealing drum 110 in arecessed area 113 that is adjacent the heating element 116. In thisconfiguration, the outer surfaces of the first drive belt 100 and theheating element 116 are substantially flush and level. The sealingportion 8 of the film 10, which is pinched between the first and seconddrive belts 100,102, preferably contacts both the first drive belt 100and the surface of the heating element 116 on one of its sides, andpreferably contacts the entire width of the second drive belt 102 on itsother side. The second drive belt 102 presses the exposed seal part 7 ofthe sealing portion 8 against the heating element 116 so that heattransfer thereto is maximized and the seal part 7 is sealed. The amountof sealing pressure applied to the sealing portion 8 can be adjusted,for example by varying the depth of the recessed area 113 so that heightof the first drive belt 100 is lowered or raised relative to the surfaceof the heating element 116.

In this configuration, formation of a seal in the seal part 7 of thesealing portion 8 is achieved as the sealing portion 8 is direct throughthe sealing segment 115 and brought in contact around the rotatingsealing drum 110 by the first and second drive belts 100,102.Preferably, the sealing drum 110 and the other rollers of the sealingmechanism 90 are configured such that contact between the sealingportion 8 and the heating element 116 of the sealing drum 110 along thesealing segment 115 is maximized during sealing. The sealing segment 115is preferably curved, the length of the sealing segment 115 beingdefined by the contact of the belts 100,102 around the circumference orperiphery of sealing drum 110. The circumference of the sealing drum 110is preferably at least 6 inches, is more preferably at least about 9inches, and is even more preferably at least about 15 inches. In oneembodiment, the drive belts 100,102 are positioned to maintain contactbetween the sealing portion 8 and at least about 40% of thecircumference of the sealing drum 110, more preferably at least abouthalf of the circumference, and still more preferably at least about 60%of the circumference, even more preferably at least about three-quartersof the circumference. In other embodiments, the belts are preferablypositioned to maintain contact between the sealing portion and at least80%, and more preferably at least 90%, of the circumference of thesealing drum. In the preferred embodiment, the sealing portion 8contacts about 90% of the circumference of the sealing drum 110 duringsealing. Additionally, the heating element 116 preferably maintains aconstant sealing temperature about at least 40%, preferably about atleast half, more preferably about at least three-quarters, and even morepreferably about the entire circumference or periphery of the sealingdrum 110. Advantageously, the amount of contact between the belts andthe drum, and the constant sealing temperature of the heating element,maximize the sealing dwell time and also minimizes the time that theheating element 116 is exposed to ambient air, which can causeoverheating and damage to the heating element and/or nearby filmmaterial. Additionally, the continuously-heating feature of the heatingelement 116 preferably produces a continuous seal with no unsealed partsor gaps that would allow air to escape from the cushion cavities.

After sealing by the sealing drum 110, the drive belts 100,102 directthe film 10 and the sealing portion 8 through the cooling segment 119 ofpath A of the sealing mechanism 90. The cooling segment 119 ispreferably separate from the sealing segment 115 and the sealing drum110, and the cooling segment 119 is also preferably curved, its lengthbeing defined by its travel around and between a set of three additionalcooling rollers 120,122,124. As seen in FIG. 3, roller 120 reverses thecurvature of the path in the cooling segment 119, compared to thecurvature, of the path about the sealing drum, shortly after leaving thesealing segment 115. This, provides a curvature in a different oropposite direction from that about the sealing drum 110, and allows thecurvature in alternating directions in the sealing and cooling segments115,119. The rollers 120,122,124 are preferably configured to helpmaintain the first and second belts 100,102 in tension about the sealingdrum 110. Rollers 120,122 are positioned to pinch the drive belts100,102 and the film 10 therebetween. Rollers 122,124 are offset fromeach other, as best seen in FIG. 3, to reduce the pressure on the filmlayers 20,22, which are sealed and cooled by the time they reach roller124, and dispense the strand of sealed cushions from the device 30 atexit zone 98. As the film 10 makes its way through the cooling segment119, the first and second drive belts 100,102 continue to pinch thesealing portion 8 and hold back the air contained in the cushions whilethe seal cools. By keeping the drive belts 100,102 in a curved patharound the rollers 120,122,124, the belts are kept taut and underincreased tension against each other and the sealing portion 8 of thefilm 10 to hold back the air before the film layers 20,22 are sealed andsufficiently cool to hold back the air without assistance. Additionally,maximizing the cooling dwell time in the cooling segment 119, while atthe same time using the drive belts 100,102 to hold back the air,ensures proper formation of the seal with an appropriate and desiredseal integrity, even at increased inflation pressures as high as about 5psi to about 8 psi or greater, upon exiting the sealing mechanism 90 atthe exit zone 98.

To provide a maximum pinching pressure between the belts 100,102 and thefilm layers 20,22 as they pass through the cooling segment 119, thespacing between the cooling rollers 120,122,124 is preferably minimizedto at most about 0.40 inches, more preferably to at most about 0.30inches, and in the preferred embodiment to about 0.25 inches.Additionally, the drive belts 100,102 are preferably kept at a tensionin the cooling segment 119 sufficient to hold back the air in theinflated cushions, but preferably this tension is minimized while stillholding back the air. Preferably, the tension of the drive belts lessthan about 8 lbs., but is at least about 2 lbs, and is more preferablyat least about 4 lbs. In the preferred embodiment, the tension of thedrive belts is about 5 lbs. In one embodiment, a cooling device 125,such as a fan or blower, can be directed at the cooling segment toincrease the rate of cooling of the seal, and in another embodiment,this cooling device is not present.

In the preferred embodiment, inflation of the cushions of film 10 isinitiated by turning on a power source of the device 30, which controlsthe drive mechanisms for the nip rollers and sealing drum, the aircompressor 33, and the heating element 116. The lead end 6 of the film10 is then manually extended from the roll 11, and directed about therollers 47,48 of the staging mechanism 40. The first longitudinal edge12 of the film 10 is fed between the rollers 52,54 of the feed-assistingmechanism 50, and the inflation channel 23 on the opposite side of thefilm 10 is fed over the nozzle 72 of the inflation assembly 70 throughthe lead opening 24. The lead end 6 is then manually directed to thefeeding zone 96 of the sealing mechanism 90, where the sealing portion 8of the film is nipped and pinched between the first and second drivebelts 100,102 and directed through the remainder of device 30.

Once the film 10 is inserted between the drive belts 100,102, theremainder of the manufacturing process is automated, as the film 10 iscontinuously pulled from the supply roll 11 by the drive belts 100,102,and directed past the different mechanisms of the device for inflationby the nozzle 72, cutting by the blade 76, and sealing by the heatingmember 116. Due to the advantages described above, the device 30 caninflate and seal the film 10 at an increased rate compared to prior artdevices, which is preferably at least about 50 ft/min, is morepreferably at least about 70 ft/min, and is even more preferably atleast about 100 ft/min. The device 30 achieves such production whileadvantageously only requiring standard power utility requirements, suchas by being capable of plugging into a standard wall outlet of 120 or240 VAC, and 15 amp. The device 30 does not require excessive inflationpressure for inflating the cushion cavities, but the device 30 caninflate and properly seal cushions at higher pressures, for example, dueat least in part to the curved path of the drive belts 100,102 and film10 through the cooling segment 119 of the sealing mechanism 90.

Other advantages of the device include the fact that the sealingmechanism can form seals in a variety of film materials, the drive beltshave an extended life before requiring replacement, the various parts(e.g. the belts, blade, sealing drum/rollers, and nozzle) are easilyreplaceable, and the device is relatively simple to control and the filmis easily threaded therein.

All of the references specifically identified in the detaileddescription section of the present application are expresslyincorporated herein in their entirety by reference thereto. The term“about,” as used herein, should generally be understood to refer to boththe corresponding number and a range of numbers. Moreover, all numericalranges herein should be understood to include each whole integer withinthe range.

While illustrative embodiments of the invention are disclosed herein, itwill be appreciated that numerous modifications and other embodimentsmay be devised by those skilled in the art. For example, the featuresfor the various embodiments can be used in other embodiments. Therefore,it will be understood that the appended claims are intended to cover allsuch modifications and embodiments that come within the spirit and scopeof the present invention.

What is claimed is:
 1. An inflatable-cushion inflation and sealingdevice, comprising: an inflation assembly configured for inflating witha fluid a cushion cavity disposed between first and second layers of afilm; and a sealing mechanism comprising a rotary sealing drum thatcomprises a periphery and a heat source providing heat to substantiallythe entire periphery, the sealing mechanism configured for receivingoverlapping portions of the first and second film layers adjacent theinflated cushion cavity, and directing the overlapping portions aboutthe sealing drum to hold the overlapping portions against each othersufficiently tightly to keep the fluid from escaping from between theoverlapping portions and to seal the overlapping portions to each otherusing the heat source over a heating portion of the sealing drumperiphery to form a longitudinal seal configured to seal the fluid inthe cushion cavity, wherein the heat source is configured to maintain atemperature around substantially the entire periphery that is sufficientto seal the overlapping portions to each other.
 2. The inflation andsealing device of claim 1, wherein: the film has a major surfaceextending longitudinally and transversely to an inflation path; theoverlapping portions are joined together; the inflation assemblycomprises a fluid conduit configured for reception longitudinallybetween the joined overlapping portions; and the device comprises ablade, wherein the sealing mechanism is configured so that film is drawnalong a path, which is curved away from the blade to pull the filmagainst the blade to facilitate cutting open the inflation channel forextraction of the fluid conduit therefrom, such that the blade isdisposed on an outside of the curve with respect to the inflationconduit.
 3. The inflation and sealing device of claim 1, furthercomprising first and second tension rollers disposed on a transverselyopposite side of the film from the overlapping portions and configuredfor gripping an opposite edge of the film, the tension rollers beingoriented at an angle to a direction transverse to an inflation path tobias said opposite edge away from the overlapping portions to improveairflow into the cushion cavity.
 4. The inflation and sealing device ofclaim 1, wherein the heat source is configured to provide substantiallycontinuous heat sufficient to seal the overlapping portions.
 5. Theinflation and sealing device of claim 1, wherein the sealing mechanismcomprises at least one belt in tension around the sealing drum to pressthe overlapping portions against the sealing drum and each other forlongitudinally sealing the overlapping portions.
 6. The inflation andsealing device of claim 1, wherein the sealing mechanism includes firstand second belts configured and disposed for nipping therebetweenoverlapping portions of the first and second film layers adjacent theinflated cushion cavity to keep the fluid from escaping from between theportions and directing the portions about a path against the sealingdrum to heat the portions sufficiently to seal the portions for sealingthe fluid in the cushion cavity.
 7. The inflation and sealing device ofclaim 6, wherein: the drum has a belt supporting portion and sealingportion, the heat source being disposed in the sealing portion; thefirst belt is disposed between the second belt and the belt supportingportion, and has a first width transverse to the path; and the secondbelt has a second width transverse to the path and wider than the firstwidth and disposed to pinch a pinched part of the overlapping portionsagainst the first belt and to pinch a sealed part of the overlappingportions against the sealing portion of the sealing drum.
 8. Theinflation and sealing device of claim 7, wherein the pinched part of theoverlapping portions is disposed transversely between the longitudinallysealed part of the overlapping portions and the cushion cavity.
 9. Theinflation and sealing device of claim 1, wherein the heating portion ofthe sealing drum periphery is at least about 50% of the drum periphery.10. An inflatable-cushion inflation and sealing device, comprising: aninflation assembly configured for inflating with a fluid a cushioncavity disposed between first and second layers of a film; and a sealingmechanism, comprising: first and second belts configured and disposedfor nipping therebetween overlapping portions of the first and secondfilm layers adjacent the inflated cushion cavity to keep the fluid fromescaping from between the overlapping portions and directing theoverlapping portions about a curved path, and a heating element disposedalong a curved portion of the curved path and operable to heat theoverlapping portions sufficiently to seal the overlapping portions forsealing the fluid in the cushion cavity; wherein the first and secondbelts are configured such that the path comprises: a sealing segment inwhich the belts hold the overlapping portions in association with theheating element to seal the overlapping portions and direct theoverlapping portions along a curve that has a curvature; and a coolingsegment, downstream of the sealing segment, in which the belts directthe sealed overlapping portions away from the heating element along acurve that has a curvature in a different direction than the curvatureof the sealing segment to allow the seal to cool sufficiently to retainthe fluid unassisted; wherein the belts pinch the overlapping portionstogether to keep the fluid from escaping from the cushion cavity in eachof the sealing and cooling segments.
 11. The inflation and sealingdevice of claim 10, wherein the path is curved in alternating directionsalong each of the sealing and cooling segments.
 12. The inflation andsealing device of claim 11, wherein the belts are configured such thatthe path comprises an intake segment upstream from the sealing segment,in which the belts pinch the overlapping portions in an unsealed stateto keep the fluid from escaping from the cushion cavity.
 13. Theinflation and sealing device of claim 10, wherein the path is curved ina first direction in the sealing segment and in an opposite direction inthe cooling segment.
 14. The inflation and sealing device of claim 10,further comprising a sealing drum that includes the heating element, thefirst and second belts configured for directing the overlapping portionsabout the sealing drum along a curved portion of the path in the sealingsegment to hold the overlapping portions against each other to keep thefluid from escaping from between the overlapping portions and to sealthe overlapping portions to each other.
 15. The inflation and sealingdevice of claim 14, wherein: the sealing drum has a belt supportingportion and sealing portion that is configured for longitudinally heatsealing the overlapping portions together; the first belt is disposedbetween the second belt and the belt supporting portion, and has a firstwidth transverse to the path; and the second belt has a second widthtransverse to the path and wider than the first width and disposed topinch a pinched part of the overlapping portions against the first beltand to pinch a sealed part of the overlapping portions against thesealing portion of the sealing drum.
 16. The inflation and sealingdevice of claim 10, further comprising rollers that direct the beltsalong the path and define the curvatures.
 17. The inflation and sealingdevice of claim 10, wherein the belts are configured to pinch theoverlapping portions to keep the fluid from escaping from the cushioncavity between the sealing and cooling segments.
 18. The inflation andsealing device of claim 10, further comprising a cutter configured anddisposed for cutting the overlapping portions in the intake segmentafter the first and second belts nip the overlapping portionstherebetween.
 19. A method of inflating and sealing an inflatablecushion, comprising: inflating a cushion cavity with a fluid, the cavitydisposed between first and second layers of a film; directingoverlapping portions of the first and second film layers adjacent theinflated cushion cavity about at least 40% of a periphery of a rotarysealing drum to hold the overlapping portions against each othersufficiently tightly to keep the fluid from escaping from between theoverlapping portions; and using a heat source providing heat aroundsubstantially the entire periphery of the sealing drum to form alongitudinal seal configured to seal the fluid in the cushion cavity,wherein the heat source is configured to maintain a temperature aroundsubstantially the entire periphery that is sufficient to seal theoverlapping portions to each other.
 20. The method of claim 19, whereinheat source provides heat continuously around substantially the entireperiphery of the sealing drum.
 21. The method of claim 19, furthercomprising: nipping the overlapping portions of the first and secondfilm layers adjacent the inflated cushion between first and second beltsto keep the fluid from escaping from between the portions; and directingthe nipped overlapping portions along a path against the sealing drum toform the longitudinal seal by moving the belts.
 22. The method of claim21, wherein: the drum has a belt supporting portion and sealing portion,the heat source being disposed in the sealing portion; the first belt isdisposed between the second belt and the belt supporting portion, andhas a first width transverse to the path; and the second belt has asecond width transverse to the path and wider than the first width anddisposed to pinch a pinched part of the overlapping portions against thefirst belt and to pinch a sealed part of the overlapping portionsagainst the sealing portion of the sealing drum.
 23. The method of claim22, wherein the pinched part of the overlapping portions is disposedtransversely between the longitudinally sealed part of the overlappingportions and the cushion cavity.
 24. The method of claim 21, wherein thefirst and second belts are configured such that the path comprises: asealing segment in which the belts hold the overlapping portions inassociation with the heating element to seal the overlapping portionsand direct the overlapping portions along a curve that has a curvature;and a cooling segment, downstream of the sealing segment, in which thebelts direct the sealed overlapping portions away from the heatingelement along a curve that has a curvature in a different direction thanthe curvature of the sealing segment to allow the seal to coolsufficiently to retain the fluid unassisted.
 25. The method of claim 24,wherein rollers are provided to direct the belts along the path anddefine the curvatures.